function transform(el, value) {
  el.style.transform = value
}

function opacity(el, value) {
  el.style.opacity = value.toString()
}

function isTouchEvent(e) {
  return e.constructor.name === "TouchEvent"
}

const calculate = (e, el, value = {}) => {
  const offset = el.getBoundingClientRect()
  const target = isTouchEvent(e) ? e.touches[e.touches.length - 1] : e
  const localX = target.clientX - offset.left
  const localY = target.clientY - offset.top

  let radius = 0
  let scale = 0.3
  if (el._ripple && el._ripple.circle) {
    scale = 0.15
    radius = el.clientWidth / 2
    radius = value.center
      ? radius
      : radius + Math.sqrt((localX - radius) ** 2 + (localY - radius) ** 2) / 4
  } else {
    radius = Math.sqrt(el.clientWidth ** 2 + el.clientHeight ** 2) / 2
  }

  const centerX = `${(el.clientWidth - radius * 2) / 2}px`
  const centerY = `${(el.clientHeight - radius * 2) / 2}px`

  const x = value.center ? centerX : `${localX - radius}px`
  const y = value.center ? centerY : `${localY - radius}px`

  return { radius, scale, x, y, centerX, centerY }
}

const ripple = {
  show(e, el, value = {}) {
    if (!el._ripple || !el._ripple.enabled) {
      return
    }

    const container = document.createElement("span")
    const animation = document.createElement("span")

    container.appendChild(animation)
    container.className = "v-ripple__container"

    if (value.class) {
      container.className += ` ${value.class}`
    }

    const { radius, scale, x, y, centerX, centerY } = calculate(e, el, value)

    const size = `${radius * 2}px`
    animation.className = "v-ripple__animation"
    animation.style.width = size
    animation.style.height = size

    el.appendChild(container)

    const computed = window.getComputedStyle(el)
    if (computed && computed.position === "static") {
      el.style.position = "relative"
      el.dataset.previousPosition = "static"
    }

    animation.classList.add("v-ripple__animation--enter")
    animation.classList.add("v-ripple__animation--visible")
    transform(
      animation,
      `translate(${x}, ${y}) scale3d(${scale},${scale},${scale})`
    )
    opacity(animation, 0)
    animation.dataset.activated = String(performance.now())

    setTimeout(() => {
      animation.classList.remove("v-ripple__animation--enter")
      animation.classList.add("v-ripple__animation--in")
      transform(animation, `translate(${centerX}, ${centerY}) scale3d(1,1,1)`)
      opacity(animation, 0.25)
    }, 0)
  },

  hide(el) {
    if (!el || !el._ripple || !el._ripple.enabled) return

    const ripples = el.getElementsByClassName("v-ripple__animation")

    if (ripples.length === 0) return
    const animation = ripples[ripples.length - 1]

    if (animation.dataset.isHiding) return
    else animation.dataset.isHiding = "true"

    const diff = performance.now() - Number(animation.dataset.activated)
    const delay = Math.max(250 - diff, 0)

    setTimeout(() => {
      animation.classList.remove("v-ripple__animation--in")
      animation.classList.add("v-ripple__animation--out")
      opacity(animation, 0)

      setTimeout(() => {
        const ripples = el.getElementsByClassName("v-ripple__animation")
        if (ripples.length === 1 && el.dataset.previousPosition) {
          el.style.position = el.dataset.previousPosition
          delete el.dataset.previousPosition
        }

        animation.parentNode && el.removeChild(animation.parentNode)
      }, 300)
    }, delay)
  }
}

function isRippleEnabled(value) {
  return typeof value === "undefined" || !!value
}

function rippleShow(e) {
  const value = {}
  const element = e.currentTarget
  if (!element || !element._ripple || element._ripple.touched) return
  if (isTouchEvent(e)) {
    element._ripple.touched = true
  }
  value.center = element._ripple.centered
  if (element._ripple.class) {
    value.class = element._ripple.class
  }
  ripple.show(e, element, value)
}

function rippleHide(e) {
  const element = e.currentTarget
  if (!element) return

  window.setTimeout(() => {
    if (element._ripple) {
      element._ripple.touched = false
    }
  })
  ripple.hide(element)
}

function updateRipple(el, binding, wasEnabled) {
  const enabled = isRippleEnabled(binding.value)
  if (!enabled) {
    ripple.hide(el)
  }
  el._ripple = el._ripple || {}
  el._ripple.enabled = enabled
  const value = binding.value || {}
  if (value.center) {
    el._ripple.centered = true
  }
  if (value.class) {
    el._ripple.class = binding.value.class
  }
  if (value.circle) {
    el._ripple.circle = value.circle
  }
  if (enabled && !wasEnabled) {
    el.addEventListener("touchstart", rippleShow, { passive: true })
    el.addEventListener("touchend", rippleHide, { passive: true })
    el.addEventListener("touchcancel", rippleHide)

    el.addEventListener("mousedown", rippleShow)
    el.addEventListener("mouseup", rippleHide)
    el.addEventListener("mouseleave", rippleHide)
    el.addEventListener("dragstart", rippleHide, { passive: true })
  } else if (!enabled && wasEnabled) {
    removeListeners(el)
  }
}

function removeListeners(el) {
  el.removeEventListener("mousedown", rippleShow)
  el.removeEventListener("touchstart", rippleHide)
  el.removeEventListener("touchend", rippleHide)
  el.removeEventListener("touchcancel", rippleHide)
  el.removeEventListener("mouseup", rippleHide)
  el.removeEventListener("mouseleave", rippleHide)
  el.removeEventListener("dragstart", rippleHide)
}

function directive(el, binding) {
  updateRipple(el, binding, false)
}

function unbind(el) {
  delete el._ripple
  removeListeners(el)
}

function update(el, binding) {
  if (binding.value === binding.oldValue) {
    return
  }

  const wasEnabled = isRippleEnabled(binding.oldValue)
  updateRipple(el, binding, wasEnabled)
}

export default {
  bind: directive,
  unbind,
  update
}
